Ablative compounds are designed to protect an article from a heat source (usually a source of extreme heat) by being coated on the article and being burned away while exposed to that heat source. The ablative compound is sacrificed to protect the article.
For example, in solid fuel rocket engines, the solid fuel is contained within a body (usually a closed tube with a nozzle, the tube being made of metal or composite material). Between the solid fuel and the body is an ablative compound. The ablative compound protects the shell from the heat generated during the solid fuel burn. The ablative compound sheds layers as it is burned off, increasing the time it takes the heat to reach the body. Typically, the protection needs to last no more than a few minutes. If there was no ablative compound, the heat of the burning solid fuel would likely burst the shell.
Such ablative compounds, typically, are rubber based. Rubbers include natural and synthetic rubbers. Synthetic rubbers include: EPDM, EPM, nitrile, etc. These compounds are filled with various natural and synthetic materials (fibers and particulates). These fillers include asbestos, mica. Examples of ablative compounds and their components may be found in the following representative, but not exhaustive, list of U.S. Pat. Nos.: 6,953,823; 6,933,334; 6,566,420; 6,265,330; 5,821,284; 5,703,178; 5,212,944; 4,732,804; 4,001,475, which are incorporated herein by reference.
The use of nanoparticles in ablative compounds for rocket engines is known. See: J. H. Koo, Polymer Nanostructured Materials for High-Temperature Applications: Fabrication, Characterization & Performance, Presentation at The FAMU-FSU College of Engineering, Tallahasse, Fla., Mar. 23-24, 2004 (jkoo@mail.utexas.edu). The nanoparticles discussed in this presentation were limited to: montmorillonite clays, carbon nanofibers, polyhedral oligomeric silsesquioxanes, carbon nanotubes, nanosilica, others (TiO2, Al2O3, etc.). Ibid., page 9.
Accordingly, there is a need for new ablative compounds that have greater high temperature performance capabilities at lesser weights.